Drawing board attachment



June 29, 1937.

FARRELL DRAWING BOA RD ATTACHMENT Filed Aug. 28, 1935 2 Sheets-Sheet l Fred FarreZZ June 29, 1937. FARRELL 2,085,304

DRAWING BOARD ATTACHMENT Filed Aug. 28, 1935 2 Sheets-Sheet; 2

Patented June 29, 1&3?"

STAES wean-i 'T ENT QFFEQE 10 Claims.

This invention relates to mechanical drawing attachments and more particularly to improvements in attachments for T-squares and the like.

I It contemplates more especially the provision of simple, inexpensive, and improved drawing board attachments that can be utilized in conjunction with T-squares and drawing boards so as to maintain a predetermined relationship therebetween.

L1 preparing mechanical drawings, a drawing board or T-square is usually employed together with other implements that are well known to draftsmen. It is advantageous to place the T- square in operative association with the drawing board and to provide means for automatically maintaining a predetermined relationship so as to improve technic and expedite the drawing operations. Numerous expedients have heretofore been devised for this purpose, but these have not proven entirely satisfactory and are too expensive to warrant their general adoption.

One object of the present invention is to provide an improved drawing board attachment that enables a predetermined relationship between the T-square and drawing board utilized in conjunction with each other in the preparation of mechanical drawings.

Another object is to provide a simple, inexpensive, and elfective T-square attachment for enabling a predetermined relationship with the drawing board.

Still another object is to provide a T-square having novel mean in association therewith for enabling adjustable attachment to a drawing board.

A further object is to provide simple and improved attachments for detachable association with a T-square to render such adaptable to a drawing board in any predetermined adjusted position relative thereto.

A still further object is to provide means in conjunction with a T-square to render such adaptable to a drawing board and enable ready adjustment relative thereto without entailing any time or inconvenience.

Other objects and advantages will appear from the following description of illustrative embodiment of the present invention.

In the drawings:

Figure 1 is a fragmentary perspective view of a drawing board and T-square having attachments embodying features of the present invention.

Figure 2 is a fragmentary plan View of a drawing board and T-square showing the attachments as illustrated in Figure 1.

Figure 3 is a sectional View taken substantially along line III-III of Figure 2.

Figure 4 is a sectional view taken substantially 0 along line of IV-IV of Figure 2.

Figure 5 is a sectional View taken substantially along line VV of Figure 2.

Figure 6 is a perspective view of the clip comprising one of the attachments shown in Figures 10 l, 2 and 4.

Figure '7 is a perspective View of a resilient member comprising one of the attachments shown in Figures 1 to 4 inclusive.

Figure 8 is a perspective view of another clip utilized in conjunction with the head of a T- square as shown in Figures 1, 2 and 3.

Figure 9 is a perspective View of a solid bar member utilized in conjunction with the tubular member shown in Figure 10. 20

Figure 10 is a perspective view of a tubular bar member utilized in conjunction with the tubular member shown in Figure 9.

Figure 11 is a fragmentary plan View of a modified attachment embodying features of the 25 present invention.

Figure 12 is a sectional view taken substantially along lines XII-XII of Figure 11.

Figure 13 is a fragmentary perspective vie; of a still further modified embodiment of the 30 present invention.

The structure selected for illustration comprises a drawing board I!) of standard or approved construction having the usual smooth finished edges II, l2, and 13. A correspondingly smooth finished edge I4 comprising a part of the customary head l5 of a T-square I6, is displaced along the drawing board edge II or edges 52 and I3 so that its elongated flat blade ll is disposed for displacement along the top surface of the drawing board l 0. As shown, the elongated blade I! is attached to head l5 to comprise what commonly known as a T-square having the usual and customary aperture [9 provided proximate to the extremity 20 of the blade 1?,

Practically all sources of supply for T-squares provide an aperture IS in the T-square blade H at substantially a fixed distance from the extremity 25 of the T-square blade l1, and this is r utilized in the present embodiment for attaching a clip 2i pressed or otherwise shaped from sheet material to present a fiat portion 22 that has a depressed tongue 23 serving as a complement to the aperture i9 provided in the blade i! of the T-square IS. The flat portion 22 of the spring clip 2! merges, in this instance, with a series of curves 2i having a sinusoidal contour stamped or otherwise impressed therein to'impart the desired resiliency to the clip 25 and to afford the elongation thereof should such be necessary in attaching the clip 2! to a T-square blade i'i having the aperture 9 at a somewhat different distance from the blade extremity 20 than which is customary or standard in such devices.

The curved clip portion 24 terminates in the flat portion 25 having depending projections 26 and 21 adapted to engage the edge 20 of the T-square blade l1, thereby springing the clip 2! in association therewith between the aperture is and the blade extremity 255. It is worthy of note that the curved sinusoidal loops 2e are spaced from each other to provide a slot 28 therebetween to accommodate a flat bar member 29 that preferably extends through a guide slot 353 provided in an upstanding flange i. The flange Si is preferably though not essentially pressed from the body of the clip 2! to serve as a guide for the bar 29 that has, in this instance, a depending offset extremity 32 with a projecting lip 33 that confronts and engages the edge [3 of the drawing board [0 when the T-square I6 is in position with its head l5 in edge contact with one of the finished edges ll of the drawing board it The solid bar 29 is telescopically received within a tubular bar member 34 that serves as a complement thereof to render such extensible for enabling variations in the length thereof for reasons which will appear more fully hereinafter. The tubular member 3 t. terminates, in this instance, in a substantially L-shaped extremity 35 which confronts the surface edge 36 of a clip 37 which has an arcuate confronting extension or arm 38 that resiliently and yieldingly grasps the head iii of the T-square it so as to be in detachable association therewith. Further, the ciip 3? has upstanding flanges or projections 39 and ift which are, in this instance, pressed from the top of the clip 31 to receive horizontally aligned slots 4! and 22 that serve as a guide member for the tubular member 34.

It is worthy of note that the telescopic association of the members 29 and 3 is maintained in a predetermined extensible position owing to the inherent friction therebetween. These complemental bar members 29-34 are, in this instance, disposed above the T-square blade H in surface contact therewith for guidance by the clips 2| and 3? that are detachably associated with the T square blade extremity 2D. and its head 55 to operatively serve as a unitary bar member which is normally urged in the direction of the T-square head if by any suitable resilient expedient such as a spring, rubber band, rubber insert or the like as commercial practice may dictate.

In the present embodiment, a rubber member or insert 43 is disposed within the L-shaped tubular bar extremity 35 and pressed against the edge surface 35 of the clip 3'! so that the bar members 28--3 i will be normally urged in the direction of the T-square head l5 to maintain the bar extremity 33in frictional contact with the edge Hi of the drawing board ii]. This maintains the T-square it in frictional association with the board if! without any possible accidental displacement and without manual manipulation or holding for accomplishing that purpose.

To momentarily release the T-square Hi from 'dom of movement for the T-square It.

frictional association or contact with the drawing board H}, the attendant grasps the flange 40 of the clip 3? with his thumb and presses the forefinger'of the left hand against the L-shaped extremity 35 of the tubular bar member 34 to compress the rubber insert 43 and slightly displace the bar members 29--34 as a unit in the direction of the drawing board edge l3 to disengage the bar extremity 33 from frictional contact with the drawing board i0 and afford free- In this instance, the rubber insert 43 is substantially U-shaped to provide bearing portions 44 and 45 that are highly yieldable and affords greater compression than otherwise possible with a solid rubber insert. The L-shaped bar'extremity 35 serves as a complement to a groove or trough as provided in the outer edge of the rubber insert 53.

With this arrangement of parts, it will be apparent that clips 2! and 32* are each readily detachable or attachable to a T-square l6 and the extensible bar members 29-3 i placed in operative position with the rubber insert 35 or other suitable resilient member assembled so that frictional engagement with the drawing board ii] is effected at one point or another depending upon the desired contact between the T-square l6 and the drawing board 10. The extensible bar members 29--3i afford adjustment for use in connection with drawing boards it of varying lengths Within the limits of the bars 29-34. Therefore, the parts thus far described may be standard for different sizes of boards and T-squares within predetermined limits and ranges.

In the modified embodiment shown in Figures 11 and 12, the clip 2i is shaped similarly to the clip 2i described in connection with the first embodiment, (Figure 6), and is attached or sprung into position identically as heretofore described in connection therewith. The bar 29 is similarly held in position and guided with the clip 2 l which, in this instance, has a flat portion 22 provided with an upstanding flange 41 which is slotted as at 48 in alignment with the slot 30 provided in the upstanding flange 3!, providing double guide flanges 3i--41 at extremities of the clip 2|. The bar 29 also terminates in an upstanding extension or offset 49, and a spring 56 is anchored between the'bar 29' and the flange 5? to normally urge the bar 29 toward the left (Figure 12), thereby keeping the bar extremity 33 in frictional contact with the edge 63 of the drawing board Hi to. accomplish a similar purpose of the foregoing structure with fewer parts.

To this end, the spring 5i! has one extremity,

5i anchored in an aperture 52 provided in an upstanding projection or bracket pressed from the bar 28'. The other extremity 54 of the spring 58 is anchored in the flange 4'! that has apertures provided therein for that purpose. As will be apparent, the upstanding flange or bracket 49 provided on the free extremity of the bar 29 enables the manipulation of the'latter and its displacement towards the right (Figure 12) against the urge cf the spring 59 to release the bar extremity 33' from frictional contact with the edge i3 of the drawing board iii to afford the displacement of the T-square blade 56' with its head id in a manner similar to that described supra.

A still further modified embodiment of the invention is shown in Figure 13 wherein a bracket 26 is permanently fastened to the T- thereby Cir square blade H by means of rivets or other suitable fasteners 56 to present a guide slot 30" in an upstanding flange 3i" proximate to the extremity 26" of the T-square blade i7. Similarly, a bracket 31" corresponding to the clip 3? of the first described embodiment (Figure 8), is permanently attached to the T-square blade i?" proximate to the head 45 by means of any suitable fasteners such as rivets 57. The bracket 3?" has spaced flanges 39 and 4% provided with slots t!" and 652" for the reception of the bar 29 and its tubular complement 3 (Figures 9 and 10) which function in a manner similar to the first described embodiment with the exception that the brackets 2i and 3? are permanently attached in this particular embodiment rather than rendered detachable as described and shown in connection with the first embodiment (Figures 1 to 10 inclusive).

It should be noted that the attachments described supra may be built in a T-square so that the extensible bars 29-3 t constitute a single unit complemental to a groove formed along the T-square blade II, and similarly the clips 2| and 3? may be formed in the body of the T-square IE to be less obstructive should commercial practice so dictate.

Various changes may be made in the embodiment of the invention herein specifically described without departing from or sacrificing any of the advantages of the invention or any features thereof, and nothing herein shall be construed as limitations upon the invention, its concept or structural embodiment as to the whole or any part thereof except as defined in the appended claims.

I claim:

1. In a device of the character described, the combination with a T-square, of means detachably associated with both ends of said T-square to engage opposite edges of a drawing board, extensible means between said edge engaging means, resilient means interposed between said T-square and said edge engaging means to frictionally hold said T-square in contact with the opposite edges of a drawing board, and means associated with the head of said T-square for releasing said edge engaging means against the normal urge of said spring means.

2. In a device of the character described, the combination with a T-square, of means detachably associated with both ends of said T-square to engage opposite edges of a drawing board, extensible means between said edge engaging means, resilient means interposed between said T-square and said edge engaging means to frictionally hold said T-square edge engaging means in edge contact with the drawing board, and means associated with the head of said T-square for releasing said edge engaging means against the normal urge of said spring means.

3. In a device of the character described, the combination with a T-square, of a spring clip attached to the free end of said T-square, a flange formed on said clip to serve as a bar guide, a bar slidably mounted for movement relative to said guide to engage an edge of a drawing board, resilient means for urging said bar toward the head of said T-square to irictionally engage the opposite edges of a drawing board when said T- square is positioned thereon, and means associated with the head of said T-square for releasing said edge engaging means against the normal urge of said spring means.

4. In a device of the character described, the

combination with a T-square, of a spring clip attached to one end of said T-square, a flange formed on said clip, there being a slot in said flange to serve as a bar guide, a bar slidably mounted in said flange slot for movement relative to said guide to engage an edge of a drawing board, resilient means for urging said bar toward the head of said T-square to frictionally engage the opposite edges of a drawing board when said T-square is positioned thereon, and means associated with the head of said T-square for releasing said edge engaging means against the normal urge of said springs means.

5. In a device of the character described, the combination with a T-square, of a spring clip attached to one end of said T-square, a flange formed on said clip to serve as a bar guide, a drawing board edge engaging bar slidably mounted for movement relative to said guide to engage an edge of a drawing board, a spring clip on the other end of said T-square, a tubular member extending from said last named spring clip toward said first named spring clip for telescopic extensible association with said slidable bar, and resilient means for urging said bar in a direction to frictionally engage one edge of a drawing board edge when the head of said T-square engages an opposite edge of drawing board.

6. In a device of the character described, the combination with a Tsquare, of a spring clip detachably associated with one end of said T-square, a flange formed on said clip to serve as a bar guide, a drawing board edge engaging bar slidably mounted for movement relative to said guide to engage an edge of a drawing board, a spring clip detachably associated with the other end of said T-square, a tubular member extending from said last named spring clip toward said first named spring clip for telescopic extensible association with said slidable bar, and resilient means associated with said last named spring clip to urge said edge engaging bar in frictional engagement with one edge of a drawing board when the head of said T-square engages an op posite edge of a drawing board.

'7. In a device of the character described, the combination with a T-square, of a spring clip attached to one end of said T-square, a flange formed on said clip to serve as a bar guide, a drawing board edge engaging bar slidably mounted for movement relative to said guide to engage an edge of a drawing board, a spring clip on the other end of said T-square, a tubular member extending from said last named spring clip toward said first named spring clip for telescopic extensible association with said slidable bar, and a resilient member interposed between said edge engaging bar and a spring clip to establish frictional engagement with one edge of a drawing board edge for maintaining said T- square in predetermined association therewith with its head engaging an opposite edge of a drawing board.

8. In a device of the character described, the combination with a T-squarc, of a spring clip attached to one end of said T-square, a flange formed on said clip to serve as a bar guide, a drawing board edge engaging bar slidably mounted for movement relative to said guide to engage an edge of a drawing board, a spring clip on the other end of said Tsquare, a tubular member extending from said last named spring clip toward said first named spring clip for telescopic extensible association with said slidable bar, and a rubber member interposed between said tubular member and one of said spring clips to establish frictional engagement between said T-square and opposite edges of a drawing board.

9. In a device 01 the character described, the combination with a T-square, of a spring clip attached to one end of said T-square, a flange formed on said clip to serve as a bar guide, a drawing board edge engaging bar. slidably mounted for movement relative to said guide to engage an edge of a drawing board, a spring clip on the other end of said T-square, a tubular member extending from said last named spring clip toward said first named spring clip for telescopic extensible association with said slidable bar, flanges formed from the material of said last named spring clip to slidably guide said tubular member, and a rubber member interposed between said tubular member and one of said spring clips to establish frictional engagement between said T-square and opposite edges of a drawing board.

10. In a device of the character described, the combination with a T-square, of a spring clip attached to one end of said T-square, a flange formed on said clip to serve as a bar guide, a drawing board edge engaging bar slidably mounted for movement relative to said guide to engage an edge of a drawing board, a spring clip on the other end of said T-square, a tubular member extending from said last named spring clip toward said first named spring clip for telescopic extensible association with said slidable bar, flanges formed from the material of said last named spring clip, there being slots in said flanges to slidably guide said tubular member, and a rubber member interposed between said tubular member and one of said spring clips to establish frictional engagement between said T-square and opposite edges of a drawing board.

FRED FARRELL. 

